To highlight changes that are imperceptible to the naked eye, researchers have developed new software that amplifies variations in successive frames of video.

The software makes it possible to actually see someone's pulse, as the skin reddens and pales with the flow of blood, and it can exaggerate tiny motions, making visible the breathing of an infant wrapped up in a neonatal intensive care unit. MIT news announces.

It’s like the equalizer in a stereo sound system (which boosts some frequencies and cuts others), except rather than the frequency of an audio signal, it focuses on color and motion changes in a sequence of video frames.

The prototype allows the user to specify the frequency range of interest and the degree of amplification. Pictured, 4 frames from the original video on top and the same 4 frames with the subject’s pulse magnified on the bottom.

Although the technique lends itself most naturally to phenomena recurring at regular intervals – such as the beating of a heart or the inflation of the lungs – if the range of frequencies is wide enough, the system can amplify changes that occur only once. So it basically different images of the same scene, allowing the user to easily pick out otherwise unnoticeable changes.

Janet Fang has written for Nature, Discover and the Point Reyes Light. She is currently a lab technician at Lamont-Doherty Earth Observatory. She holds degrees from the University of California, Berkeley and Columbia University. She is based in New York.
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